TY  - RPRT
TI  - Wick's theorem for charged spin systems.
AU  - C Gros
AU  - MD Johnson
PY  - 1989
DO  - 10.1103/physrevb.40.9423
UR  - https://pubmed.ncbi.nlm.nih.gov/9991458/
ID  - 9991458
ER  -